The present invention relates to the improvement of a load-driving integrated circuit device having an integrated circuit of semiconductor opening/closing devices for performing frequent on/off control of an energization current for an electric load and for controlling the conduction duty rate, which is the proportion of the circuit-closing time to the opening/closing period, so as to adjust and control the load current; in particular, the present invention relates to a load-driving integrated circuit device that copes with occurrence of a local abnormality related to the semiconductor opening/closing devices and makes it possible to perform continuous operation.
There is publicly known a load-driving integrated circuit device that adjusts the number of parallel-connected opening/closing devices, preliminarily and separately arranged, so as to make the opening/closing devices match with a required current capacity. For example, according to FIG. 2 in Japanese Patent Application No. JP-A-H07-263632 (ABSTRACT, FIGS. 1 and 2, Paragraphs 0027 and 0028), listed below, when the logic of the control signal B is changed from “L” to “H”, the transistor 7 is connected in parallel with the load-driving transistor 10 and in response to this, selection of transistors 11 and 12 is performed, i.e., there is disclosed a technology in which in order to change the apparent transistor size, selective connection switching of a plurality of transistors is implemented so as to increase or decrease the number of parallel-connected transistors.